In the conventional liquid air cell, there is a problem that when iron is used as an anode active material, oxide and hydroxide are precipitated on an iron surface and thus cycling performance decreases. Therefore, studies have been carried out into the increase in pulverization, etc. of the anode active material. Patent Literature 1 discloses a metal-air battery using a composite electrode material as an anode active material, the composite electrode material having a carbon base material and iron oxide particles mainly containing Fe3O4 and being supported on the carbon base material and the particles have a D90 of 50 nm or less.